package madixin.t63;

class Solution {
    //https://leetcode-cn.com/problems/unique-paths-ii/solution/bu-tong-lu-jing-ii-by-leetcode/
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        if (obstacleGrid == null || obstacleGrid.length <= 0 || obstacleGrid[0].length <= 0) {
            return 0;
        }

        int m = obstacleGrid.length;
        int n = obstacleGrid[0].length;
        if (obstacleGrid[0][0] == 1 || obstacleGrid[m - 1][n - 1] == 1) {
            return 0;
        }
        int[][] dp = new int[m][n];
        for (int i = 0; i < m; i++) {
            if (obstacleGrid[i][0] == 0) {
                dp[i][0] = 1;
            } else {
                break;
            }
        }

        for (int i = 0; i < n; i++) {
            if (obstacleGrid[0][i] == 0) {
                dp[0][i] = 1;
            } else {
                break;
            }
        }

        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                if (obstacleGrid[i][j] == 1) {
                    dp[i][j] = 0;
                } else {
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
                }
            }
        }

        return dp[m - 1][n - 1];
    }

    public static void main(String[] args) {
        Solution s = new Solution();
        //int[][] a = new int[][]{{0, 0, 0}, {0, 1, 0}};
        //System.out.println(a.length);
        //System.out.println(s.uniquePathsWithObstacles(new int[][]{{0, 0, 0}, {0, 1, 0}, {0, 0, 0}}));
        //System.out.println(s.uniquePathsWithObstacles(new int[][]{{0}}));
        System.out.println(s.uniquePathsWithObstacles(new int[][]{{0, 0, 0}, {0, 1, 0}}));
    }
}